DESCRIPTION: (Adapted From the Applicants Abstract): This proposal deals with the role of several neurotrophic factors in the fetal development of sensory neurons that innervate taste buds, and interactions between fetal cell types in the morphogenesis of mature taste organs. The P.I. will be able to use an organ culture system developed in her laboratory as an essential resource for all these goals. Firstly, the role of neurotrophic factors in supporting the development of the neurons the innervate taste buds have a different neurotrophic dependence than neurons from other sensory ganglia. Such dependence will be measured in terms of morphometric studies on neurite outgrowth and in terms of the development of critical electrophysiological properties in the sensory neurons. Secondly, the organ culture system will allow detailed analyses of any potential induction roles that embryonic tongue epithelium and mesenchyme may play in the formation of gustatory papillae. Finally, the interactions of the growing neurites of sensory neurons with developing taste buds will be examined. The later two aims will be approached by establishing mixed cultures of epithelium and mesenchyme or papillae and ganglia of different ages and morphogenetic potential. These data will form a significant body of knowledge about the development of the peripheral gustator system.